Thanks, I currently use Band-in-a-Box® for Windows Version 2018 (520)

I am not sure whether Natural Arrangements would really cater for that. Disabling it would mean that complex chords would not get re-interpreted I guess. But in my case, I have simple chords, that I want interpreting in a certain way.

Maybe I should test it and look at the midi data to see how it worked.
But with Realtracks, the midi data is not always shown it seems.

The results are a bit hit and miss:
For example, an Am#5 is sometimes played as a normal Am chord with a perfect 5th. If I rename the chord as F/A, BIAB thinks it's ok to embellish with a Bb note.